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<html>
  <head>
    <meta
      name="viewport"
      content="minimum-scale=1.0, width=device-width, maximum-scale=1.0, user-scalable=no"
    />
    <meta charset="utf-8" />
    <title>Pure Functions</title>
    <script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>
  </head>
  <body>
    <h1>Pure Functions</h1>
    <p>Open the console</p>
    <script type="text/babel">
      var frederick = {
        name: "Frederick Douglass",
        canRead: false,
        canWrite: false
      };

      const selfEducate = person => {
        person.canRead = true;
        person.canWrite = true;
        return person;
      };

      //
      // still impure, mutates the original object
      //

      console.log(selfEducate(frederick));
      console.log(frederick);
    </script>
  </body>
</html>
